1. Field of the Invention
The present invention relates to a digital camera having a solid-state color image pickup element, and a signal processing method and a signal processing apparatus for it, and more particularly to a digital camera which suppresses generation of a purple false color after taking a white balance, and a signal processing method and a signal processing apparatus for it.
2. Description of the Related Art
In a CCD or CMOS image sensor using primary color filters, usually, the sensitivity for green (G) is higher than the sensitivities for red (R) and blue (B), but the saturation levels for red, green, and blue are substantially equal to each other. When a white balance is taken, however, the red and blue gains are larger than the green gain in order to compensate the sensitivity ratio, with the result that the green saturation level is lower than the red and blue saturation levels.
When the green saturation level is made coincident with the red and blue saturation levels, there arises a problem in that a purple false color is generated in a high brightness region. Conventionally, therefore, the red and blue saturation levels are clipped in accordance with a pixel for detecting green to suppress a purple false color, as described in Japanese Patent No. 2,557,620.
When the red and blue saturation levels are clipped at the green saturation level as described above, generation of a purple false color can be suppressed. However, clipping of the red and blue saturation levels causes another problem that the dynamic ranges of red and blue are reduced.